Conventional graphics processors are exemplified by systems and methods developed to reduce bandwidth between a memory storing a z buffer and a graphics processor accessing the z buffer. Conventionally, some graphics processors compress z values prior to writing them into the z buffer and decompress the z values after reading them from the z buffer. The compression and decompression operations require additional computations, beyond the typical z data processing to perform hidden surface removal. The additional computations may require dedicated logic used only for that purpose or the additional computation may be performed using general purpose logic. In either case, the performance or efficiency of the graphics processor is negatively impacted.
There is thus a need for a z compression and z decompression which reduces the bandwidth used by a graphics processor accessing the z buffer and minimizes the number of additional computations needed to perform hidden surface removal.